The Pentagon's defence scientists want to create an army of cyber-insects that can be remotely controlled to check out explosives and send transmissions.

The idea is to insert micro-systems at the pupa stage, when the insects can integrate them into their body, so they can be remotely controlled later.

Experts told the BBC some ideas were feasible but others seemed "ludicrous".

A similar scheme aimed at manipulating wasps failed when they flew off to feed and mate.

The new scheme is a brainwave of the Defence Advanced Research Projects Agency (Darpa), which is tasked with maintaining the technological superiority of the US military.

It has asked for "innovative" bids on the insect project from interested parties.

Darpa believes scientists can take advantage of the evolution of insects, such as dragonflies and moths, in the pupa stage.

"Through each metamorphic stage, the insect body goes through a renewal process that can heal wounds and reposition internal organs around foreign objects," its proposal document reads.

The foreign objects it suggests to be implanted are specific micro-systems - Mems - which, when the insect is fully developed, could allow it to be remotely controlled or sense certain chemicals, including those in explosives.